Moanica D'kay its the main antagonist of Welcome to Monster High, the reboot movie of the Monster High franchise.
She lives in a cemetary with her family. She hate normies (humans) since she and other monsters have been forced to hide in the shadows for centuries. She has a group of zomboy minions. Unlike the other monsters, she doesn't see the equality between them and the normies, so she wants to destroy all of the normies and take everything. After she was defeated by the ghouls, she promised that she will take her revenge and someday put an end to Monster High.